Synthesis Of Mannose-Rich Exopolysaccharide By Rhodotorula Glutinis 16P Co-Cultured With Yeast Or Bacteria
Exopolysaccharides from the lactose-negative yeast Rhodotorula glutinis 16P were synthesized by co-cultivation with the yeast Kluyveromyces lactis MP11 or with the homofermentative lactic acid bacteria Lactobacillus helveticus 9A in a cheese whey ultrafiltrate. Exopolysaccharides were produced by lactose hydrolysis, performed by two pathways: with β-galactosidase from Kluyveromyces lactis MP11 which assimilates glucose and galactose; with β-galactosidase and Lactobacillus helveticus 9A which uses lactic acid. By growing the two mixed cultures maximum yield was obtained as follows: 11.4 g/l and 15.8 g/l, respectively. Structural units of the carbohydrate composition of the two polymers are mannose (72.4-63.5%), glucose (2.0-15.9%), galactose (25.3-19.8%) and xylose (3.6-4.3%). Mannose dominated in the polysaccharide compositions.